'\" te
.\"  Copyright 1989 AT&T
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.TH MSGDSIZE 9F "Jan 16, 2006"
.SH NAME
msgdsize \- return the number of bytes in a message
.SH SYNOPSIS
.LP
.nf
#include <sys/stream.h>



\fBsize_t\fR \fBmsgdsize\fR(\fBmblk_t *\fR\fImp\fR);
.fi

.SH INTERFACE LEVEL
.sp
.LP
Architecture independent level 1 (DDI/DKI).
.SH PARAMETERS
.sp
.ne 2
.na
\fB\fImp\fR\fR
.ad
.RS 6n
Message to be evaluated.
.RE

.SH DESCRIPTION
.sp
.LP
The \fBmsgdsize()\fR function counts the number of bytes in a data message.
Only bytes included in the data blocks of type \fBM_DATA\fR are included in the
count.
.SH RETURN VALUES
.sp
.LP
The number of data bytes in a message, expressed as an integer.
.SH CONTEXT
.sp
.LP
The \fBmsgdsize()\fR function can be called from user, interrupt, or kernel
context.
.SH EXAMPLES
.sp
.LP
See \fBbufcall\fR(9F) for an example that uses \fBmsgdsize()\fR.
.SH SEE ALSO
.sp
.LP
.BR bufcall (9F)
.sp
.LP
\fIWriting Device Drivers\fR
.sp
.LP
\fISTREAMS Programming Guide\fR
